California and 18 other states said they would sue to stop the Trump administration proposal to weaken Obama-era federal fuel efficiency standards, arguing the United States has an obligation to protect the environment for future generations. Under the Obama-era plan, the target was 54.5 miles per gallon by 2025.
The proposal to roll back anti-pollution efforts is in line with President Donald Trump's decision previous year to abandon the 2015 Paris Agreement, under which countries agreed to take steps to mitigate global warming.
Democrats have called for the auto sector and states like California to reach a compromise on stricter fuel efficiency and emissions standards.
The administration's rule aims to preempt California's Clean Air Act (CAA) waiver and argues that it should be pulled entirely. The company went on to say the "proposal includes a range of options, and we will carefully evaluate how each aligns with FCA's goals of continuous improvement in vehicle efficiency".
The rollback would undermine efforts by California and several other states to meet commitments the US made in the Paris agreement on climate change.
"I feel like we have a very good and strong case", state Attorney General Xavier Becerra said. Critics said it would accelerate climate change and increase fuel prices. Several other states followed California's guidelines, creating a fragmented set of standards across the country.
In a 978-page document (pdf) released on August 2, the EPA and the National Highway Traffic Safety Administration are also proposing to retract a waiver issued to California in 2013, which enabled the state to set its own stricter emissions standards. The plunge in natural gas prices and other market forces have steadily lowered the climate impact of utilities, but transportation is proving more stubborn.
But the Trump administration has consistently criticized the policy as bad for the auto industry.
California is expected to challenge the withdrawal of the waiver in court.
The Trump administration's proposal would freeze fuel-efficiency standards at 2020 levels - about 37 miles per gallon by 2026, down from the Obama administration's almost 47 mpg - and weaken electric vehicle mandates.
Environmental groups are already expressing their outrage over the plan.
The administration also projects the efficiency rules would drive up the price of cars enough to push some buyers out of the market, leaving them to remain in older vehicles lacking life-saving new technologies like assisted braking and blind spot warning. In May, California and 16 other states filed a preemptive lawsuit arguing the rollback would be illegal. The affordability argument also ignores thousands of dollars of saving in fuel costs for each driver over the life of a vehicle, opponents of the rollbacks said.
Heidi King, deputy administrator of the National Highway Traffic Safety Administration, said the freeze would reduce highway deaths by 1,000 per year "by reducing these barriers that prevent consumers from getting into the newer, safer, cleaner, more fuel-efficient cars". They've argued that the Obama-era standards Trump proposes to sweep aside are outdated, established when the USA was over-reliant on foreign oil, and that they don't reflect huge increases in US exports of crude oil and petroleum products since then.